1. Field of the Invention
The present invention relates to a method for automatically and successively cultivating tissues or cells of a living body, and more particularly to such method for cultivating the tissues or cells under controlled conditions in a gas-sealed culture box excluding bacteria contamination.
2. Description of the Prior Art
In the present instance, the techniques for the culture of such tissues, especially cells of a living body have been of fundamental importance in many fields such as medicine, biology and related fields.
On the other hand, recent developments or advances in the study of viruses and rickettsia have enabled scientists to produce a variety of new vaccines. These vaccines must be steadily produced for the needed amount of products which are stable in quality Heretofore, though the vaccines are usually produced by using hen's eggs as a culture base, it is desirable for the culture base to be tissues or cells of a human body from the immunological point of view. It is known, that a person who is repeatedly inoculated with the egg-based vaccines produced by the conventional manner sometimes may develop an egg allergy. This has been one of the problems to which the present invention is directed and necessitates a large quantity of tissues or cells of the human body, which were cultured by a standardized manner.
Due to the difficulty of subculturing the tissues or cells of the human body, it was previously believed that a stable cultivated "mass" of such tissues or cells can not be obtained except for the specific cells or tissues; later the technique for cultivating the tissues or cells of the living body in an incubator or a culture box, the inside of which is maintained in a specific gaseous atmosphere, was developed. Due to this culture technique, it has become possible to cultivate even the distinctive cells of the human body such as liver cells, nerve cells and hypophysis cells.
However, the conventional tissue or cell culture technique is difficult to standardize for the reasons described hereinafter. In the cell or tissue culture technique in a gaseous atmosphere, which is believed the most effective method at the present instance in this field, it is inevitably necessary to frequently remove the culture container containing the tissues or cells from the gas-sealed culture box or the incubator during the cultivation in order to microscopically observe the multiplication conditions of the tissues or cells. According to the results of such observation, a technician who is skilled in the cell or tissue culture technique then performs the necessary manipulation for the subculture of the cells or tissues. Therefore, the cells or tissues in the culture container are exposed to the air for considerably long periods of time during such observation and manipulation, and thus the culture environment for the cells or tissues will be greatly changed. In addition to these changes of the culture conditions, the cells or tissues will be contaminated by the air itself and any bacteria or germs that may be contained in the air. Furthermore, the number of technicians who are skilled in the cell or tissue culture technique is quite insufficient, since at least two years is needed for training.
Since the standardization of the cell or tissue culture is very difficult for the reasons described above, completely opposite conclusions are sometimes obtained by different scientists who have respectively studied the same item.
Therefore, instead of a technician a scientist must spare his time and attention for the cell or tissue culture which is not his essential work, instead of devoting his effort to original medical or biological studies. This is a common concern among scientists of various fields, and thus the unification, standardization and automation of the cell or tissue culture are needed.